Joining a new legacy codebase can often feel like walking into a minefield, especially when working with a distributed team. As a senior software developer, I’ve faced numerous challenges in understanding unclear architectural patterns, dealing with tightly coupled code, and implementing improvements without introducing regressions. These challenges become even more pronounced when collaborating across time zones with team members who have varying levels of familiarity with the codebase.

Over the years, I’ve found that architecture testing is not just a nice-to-have—it’s a necessity. And when it comes to Laravel projects, PestPHP has proven to be an invaluable tool in maintaining clarity, scalability, and consistency in legacy codebases.

In this article, I’ll share how PestPHP simplifies architecture testing, grounded in real-world scenarios I’ve encountered, and how it can help distributed teams improve legacy codebases while minimizing friction.

What Is PestPHP?

PestPHP is a modern testing framework for PHP that emphasizes simplicity and developer experience. While it builds on PHPUnit, PestPHP’s streamlined and expressive syntax makes it a joy to work with. For someone who values clean code and maintainability, PestPHP is a natural fit.

Key Features of PestPHP:

  • Minimalist syntax for concise test writing.
  • Built-in support for data providers and custom test hooks.
  • Plugins for extending functionality.
  • Readability-focused output for better debugging.

Example: Comparison of PestPHP and PHPUnit Syntax

Here’s a comparison of how the same test might look in PestPHP versus PHPUnit, based on my experience:

PestPHP:

test('an example endpoint returns a 200 status', function () {
    $response = $this->get('/example-endpoint');
    $response->assertStatus(200);
});

PHPUnit:

public function testExampleEndpointReturns200Status()
{
    $response = $this->get('/example-endpoint');
    $response->assertStatus(200);
}

This simplicity is one of the reasons I’ve transitioned entire projects to PestPHP. It eliminates boilerplate code, allowing developers to focus on the essence of their tests.

Why Architecture Testing Matters in Laravel

In one of my previous projects, a wallet application for managing transactions, the challenges of working on a legacy codebase were magnified by the lack of proper architectural patterns. Controllers were overloaded with business logic, service container bindings were inconsistent, and debugging took up a significant portion of development time.

These issues became even more problematic with a distributed team. Different contributors interpreted architectural expectations differently, leading to inconsistent implementations. This is where architecture testing became indispensable. It allowed us to:

  • Ensure compliance with design patterns (e.g., Repository, Service Layer).
  • Validate proper dependency injection.
  • Maintain a consistent directory structure and naming conventions.
  • Enforce separation of concerns (SoC).

By introducing architecture tests, we not only improved the quality of the codebase but also created a shared understanding of architectural goals among team members, regardless of their location.

Setting Up PestPHP in a Laravel Project

  1. Install PestPHP Begin by installing PestPHP in your Laravel application: 
    composer require pestphp/pest --dev
  2. Initialize Pest Next, initialize Pest to set up the required configuration: 
    php artisan pest:install
  3. Add Plugins For Laravel-specific features, include the Laravel plugin: 
    composer require pestphp/pest-plugin-laravel --dev

Writing Architecture Tests with PestPHP

Here’s how I’ve used PestPHP to tackle real-world scenarios in architecture testing, particularly when working with legacy codebases.

1. Testing Directory Structure

One of the first steps in organizing a legacy codebase is ensuring a consistent directory structure. This test helped us create order from chaos:

it('has the correct directory structure', function () {
    $directories = [
        'app/Models',
        'app/Http/Controllers',
        'app/Services',
        'app/Repositories',
    ];

    foreach ($directories as $directory) {
        expect(is_dir(base_path($directory)))->toBeTrue();
    }
});

2. Validating Dependency Injection

Inconsistent dependency injection was a recurring issue. This test ensured controllers adhered to dependency injection practices:

it('uses dependency injection in controllers', function () {
    $controllerPath = base_path('app/Http/Controllers');

    $files = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($controllerPath));
    foreach ($files as $file) {
        if ($file->getExtension() === 'php') {
            $content = file_get_contents($file->getRealPath());
            expect(str_contains($content, 'new';))->toBeFalse();
        }
    }
});

3. Testing Service Container Bindings

While refactoring a payment integration, we used PestPHP to verify that services were correctly bound, preventing runtime errors:

test('service container binds the correct implementation', function () {
    $service = app(AppContractsPaymentService::class);
    expect($service)->toBeInstanceOf(AppServicesMpesaPaymentService::class);
});

4. Ensuring Naming Conventions

Naming conventions can spiral out of control in legacy projects. We enforced them with this test:

it('follows naming conventions', function () {
    $services = glob(base_path('app/Services/*.php'));
    foreach ($services as $service) {
        expect(str_ends_with($service, 'Service.php'))->toBeTrue();
    }

    $repositories = glob(base_path('app/Repositories/*.php'));
    foreach ($repositories as $repository) {
        expect(str_ends_with($repository, 'Repository.php'))->toBeTrue();
    }
});

Benefits of Using PestPHP for Architecture Testing

  1. Readable Syntax: Simplifies collaboration by making tests easier to understand.
  2. Extensibility: Tailor tests with plugins and custom hooks for unique project needs.
  3. Improved Debugging: PestPHP’s output makes identifying failures straightforward.
  4. Encourages Testing: Its simplicity lowers the barrier to entry for writing tests, even for architecture-level checks.
  5. Team Alignment: Standardized architecture tests provide clarity and alignment in distributed teams.

Best Practices for Architecture Testing in Laravel

  • Automate Architecture Tests: Integrate them into your CI/CD pipeline to catch issues early.
  • Modular Organization: Keep tests organized in directories like tests/Architecture for clarity.
  • Educate Your Team: Share knowledge on PestPHP to maintain consistency across the team.
  • Regular Review: As your application evolves, ensure your architecture tests stay relevant.

Conclusion

Working with legacy codebases in distributed teams can be challenging, but architecture testing with PestPHP provides a roadmap for improvement. From validating service layers to enforcing naming conventions, PestPHP helps turn disorganized codebases into maintainable and scalable systems.

For me, PestPHP has become a cornerstone of development, especially in ensuring consistency and quality when collaborating with diverse teams.

If you’re ready to embrace better testing practices, start exploring PestPHP today. And if you have questions or stories to share, drop a comment below—let’s learn together.

Tags: